Scribing and inspecting gauge for circular form tools



Sept; 2, 1952 SQMMA ETAL 2,608,764

SCRIBING AND INSPECTING GAUGE FOR CIRCULAR FORM TOOLS Filed Aug. 1, 1949 s5 w/a 5, 3

4/ 39 36 37 gen 0 V I 2/ 29 INVENTORS 2/ 1 a I HERMAN RSOMMA x BY HENRYJ. 30mm ATTX Patented Sept. 2, 1 952 fl u ivi'reo STAT SCRIBING AND INSPECTING GAUGE FOR? 7 1 CIRCULAR FORMTQOLS Herman R. Somma and Henry J. Somma, Water- 1 bury, Conn., assignors to The Somma Tool Com- 5 Dany, Waterbury, Co

vnectic'ut nn;, a .corporatio'nof Con- Application August 1', 1949, S'erial hlo. 107,886

" 6'Olaims.

- Thisinvention relates to gauges, andmore particularly to a scribing and inspection gauge which will facllitatethe' provision of accurate cuttin edges upon circular form tools of thefity pe'employed for shaping the work in automatic screw machines. One object or the invention is to provide a auge of the above nature having a scriber guide which will enable the cutting surface to be ac curately laid out at a Zero or other rake angle on th'e tool without regard-tojthe specific peripheral form of the tool. f" Another object is to provide a-gauge of the above nature having a tur'nable sori'ber guide which isreadily adjustable for selectively laying out'ei-ther standard or other cutting surfaces. Another objectis to provide a gauge of the above nature which is provi'ded' with an adjustableinspecting disk which may be employed to determine the'rake angle of the cutting surf-ace ina form tool withoutdisturbing the adjustment of the scriberguide;

Another object is to provide a device-of the above nature in which the scriber guide so constructed as to permit direct observation of the form tool during the scribing operation. 1

A further objectis toprovide a gauge of the above'na-ture which-will besimplein construction, inexpensive to. manufacture, easy to 'use and manipulate. compact, ornamental in appearance, and very efiicient and durable in use. ,7

With these and other objects in view, there has, beenillustrated on the accompanying drawingone 'form in which the invention may conveniently be embodied in practice.

In the drawing,' v Fig. 1 is a plan view of the improved scribing and inspection gauge showing a form' toolse' cured'th'ereto in position forjinspectionQ Fig. 2 is a front elevationof the same, partly in section, showing a scriber attached thereto by a cord.

Figj 3 isa partial cross sectional view, showing f the scriber guide on an enlarged scale, taken on' the line 33 of Fig. 1, and with the scriber in operating position.-

(c1. sis-.32)

Fig. 4 is a partial cross sectional view, taken on the line 4 4 of Fig.1, showingthe' inspecting V disk-onan enlarged scale. H i "Referring nowtothe drawings, in which like reference numerals denote corresponding parts" throughout the several views, the numeral 10in dicates one form of the improved gauge com'prising' a fiat base plate ll, of stainless steel or other suitable material, and generally rectangular in form but preferably-=-rounded at its corners to facilitate handling;

--''A'circulariormtool T v(which is adapted to be provided with a: cutting edge E7) may be held firmly'a gainst' thelower'surfaceof the base plate I I by means ofa threaded plug I2 which is adapted to be engaged in a tapped central aperture l3 in said form tool. The plug [2 is provided withareduced stud 14 rotata'bly disposed in an aperture offset from the center of the base plate H, said stud having a knob l 5-he1 d thereon by a' set screw l6. Thus, it will beseen that the form t'ool T may be applied to the plug 12 and brought into firm clamping engagement=with the lower surface of the base plate I! by manual rotation of the knob 15.

It'will be noted, however, that a slight reverse turning'movement o'i .the knob l5and the plug [2' will serve to loosen'the tool T so as to permit its rotation with respectto the base plate H for a purpose to be described hereinafter. v

In order to hold aninspection diskl'l and a scriber'guide I 8 forrotary adjustment, opposite endportio'nsof the base plate ll are-respectively formed with large circular apertures-J9, having narrow' inwardly-extending lower flanges Z l, 22said apertures I9. 20 beingdisposed with their centers in accurate vertical alignment with the outer periphery of the form tool T.

The inspecting disk I'I is formed of a suitable flat-transparent material which will permit visual observation of the form tool T therethrough, and is provided with a. peripheral ring or bezel 23 which may be crim-ped or otherwise firmly attached' to the edges of said transparent disk,

I I1 is rota-tably thereof, provisi'on'is made 'of' a pair of retaining screws 24, 25,- which are diametrically opposed to each other and which are mounted in thebase plate H. The retaining screws'2'4, 25"are provided with washerslfir 21 which overlap the ring 23, said ring being of sucha thickness as to project slightly above the upper surface of the plate I l Thus, the washers 26, 2! frictional-'- 1y engage edge portions of the inspecting disk I! and will permit said disk to be rotated when desired by the operator, provision being made of a pairof integral upwardly projecting handles 28,

forthis purpose;

In order to permit the rake angle of the cutting edge Eto' be determined, thelower su-rf-ace'of the "inspecting disk' 11 is provided with a diametrical 3 hair line 29, and an index mark 30 is provided in the upper surface of the ring 23 in alignment with said hair line.

Rake angles in the tool T may be determined by the hair line 29 and the index mark 30 in conjunction w'ith either of two sets of numbered graduations 31, 32, respectively, which are so arranged that the zero graduation in each set will indicate a desired standard offset of the cutting surface from a radial plane of the tool.

The scriber guide I8 is in the form of .abar which is held in a diametric position above the aperture 20 by means of an integral ring 33, supported upon the flange 2 2. The scriber guide I8 is provided with a longitudinal vertical slot 34 which is accurately aligned with a diameter of the aperture 23, and which is out inwardly through the ring 33 at one end of the scriber guide IE, but which terminates short of the opposite end of said guide. 1

It will be seen that the slot 34 is parallel-sidcd, and has a vertical depth which; i s much greater than its width, said depth preferably being at least four times the width of the slot v3t in order to accurately guide a hat, pointed scriber 35 which has a snug sliding :fit insaid slot.

Thus, it will be seen that the scriber 35 will be accurately guided in the slot 34 when used to scribe a line upon the tool T. Itwill also be seen that the scriber guide I8 is relatively narrow, as mpa ed with th diameter of the ring.3.3, and that said-guide has lower converging bevelled side portions 33, 31 which permit the lower end of the scriber 35 to be clearly visible to the operator during the scribing operation, so as to facilitate the use thereof.

In order to ret n the scri er uide ring .33 frictionally against the flange 22 the aperture 2,0, provision is made of a pair-oi Washers 38, 39. which overlap the ring 33, and are held by means of retaining screws 41L 41,.mounted in the base pla e I l. The thickness of the ring 33 is such. as to cause said ring to project slightly above the upper surface of the base plate It so that said ring will be positively engaged by the washers .33, 39, thus Irictionally held against accidental turning in the aperture 129.

The ring 33 is prov ded withan. index mark. which is aligned with theslot 34 so as. to accurately indicate a standard ofifset or degree of rake le u on either of two umbered sets of graduations 43, 44 marked upon the base plate H, l

The scriber 35 is preferably attachedto. the base plate H bymeans oi a chain or cord-35a, so that the gauge ID will always beaccompanied by the scriber and the latter cannot become lost.

The gau may of course, be made, inanr desired size. in order to accommodate different standard sizes of form tools, as for-example, the types and sizes which are known as No. 00 B8 8, No. 0- 38:5, and No. 2 B&S. It will be understood that, in each instance, the threaded plug 12 will :be so constructed as toproperly fit the central aperture of each particular siz of term tool, while the base plate H will be so constructed that the centers of the apertures l9,'20 will be disposed at the periphery of the form tool 'I.

tached to the threaded plug l2, and then turned until the cutting edge E is disposed in alignment with the center point of the hair line 29, after which the knob IE will be tightened so as to clamp the tool, T firmly against movement.

The inspection disk ll will then be manually rotated by means of the projections 28 until the hair line 29 coincides with the cutting surface of the tool T, whereupon the position of the cutting surface will be indicated by the position of the index mark 30 adjacent the graduations 3! or 32, as the case may be.

It it should now be desired to scribe the locations of a new or different cutting surface upon the tool T, in order to facilitate the grinding f anew cutting edge, the knob I5 will be loosened so as to permit said tool to be rotated. The locathe graduations 43 or 44. I p

The scriber 35 will then be inserted downwardly through the slot 34 and drawn longitudinally in said slot in such a manner that the point of the scrlber 35 will scratch a line in a coating of Prussian blue or other suitable compound which will have been previously applied to the tool T, thus providing a clear mark thereon which will facilitate the grinding of the tool at the proper location and angle. 4 Y

It will, of course, be understood that the tool T willbe removed from the gauge 10 prior to the grinding operation, the removal being accomplished merely by turning the knob l5 in a counterclockwise direction.

One advantage of thegauge'herein disclosed, is that the relatively great depth of the scriber guide slot 34 will .permit cutting surfaces tobe accurately marked upon tools having irregular or complicated edge configurations, inasmuch as the s'criber 35, when in use, will always be maintainedin a plane at right angles to the side surfaceof the tool T. V

While there has been disclosed in this specification one form. in which. the invention may-be embodied it is to be understood that this form' is shown for the purpose of illustration only,a' nd that the invention is not to be limited to the sp ciflc disclosure, but may be modified and embodied-in various other forms, without departing: from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

I Having thus fully described the invention, what is claimedas-ne'w. and for which itis desiredto secure Letters Patent, is: g

l. .a gauge for circular form tools, a-base plate having means for clamping a form tool of predetermined diameter against one face thereof, a circular aperture in said plate, the center ofsaid aperturebeinglocated in alignment witha point on the periphery of the term tool held by said clampin means, and a scribcr guide rotatably.-mounted in said aperture, said scrlber guide comprising a slotted bar which is held in a diametrical position adjacent-said aperture by means of a ring mounted for rotating movement in said aperture. I

.2. The invention as defined in claim 1, wherein said. ring. is supported upon an, inwardlyextending flange in said'aperture, and including frictional means mounted upon said plate for retaining said ring against said flange.

3. The invention as defined in claim 1, wherein said bar is offset above said ring in a direction perpendicular to the plane of said ring, whereby the scratching action of a scriber in said slot may be observed by the operator.

4. In a gauge for a circular form tool, a base plate having means for clamping the form tool against one face thereof, a circular support member rotatably mounted in a through aperture within said base plate, and a scriber guide integrally affixed diagonally across said support member and perpendicularly offset from the plane of said face, said scriber guide having a slot in a plane at right angles to said face, said slot having a depth greater than the width thereof, whereby a scriber may be accurately guided by said slot.

5. The invention as defined in claim 1, wherein said clamping means comprises a threaded plug adapted to be received in a tapped central aperture in a form tool, a stud integral with said plug and extending rotatably through an aperture in said base plate, and a knob secured to said stud in abutting relationship with the opposite face of said base plate.

6. In a gauge for circular screw machine form tools, a substantially rectangular base plate having means for clamping a screw machine form tool of predetermined diameter against one face of said base plate, said base plate having a closed circular aperture the center of which is located in alignment with a point on the periphery of the screw machine form tool held by said clamping REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 773,896 Richards Nov. 1, 1904 919,786 Simmons Apr. 27, 1909 1,553,878 Romig Sept, 15, 1925 2,402,890

Hochreiter June 25, 1946 

